Efficient Glaucoma Detection from Retinal Fundus Images Using a Lightweight DeiT-Small Vision Transformer and Test-Time Augmentation

Abstract

Glaucoma is one of the major causes of permanent blindness in the world, and since the progressive nature of the disease leads to considerable damage of the optic nerve before diagnosis, there is a need to develop precise and effective automated screening tools. This paper suggests the implementation of a lightweight vision transformer network for glaucoma screening based on the DeiT-Small architecture. The images were downsized to 224 × 224 resolution and transformed into patches. Four transformer blocks were frozen while the other blocks were fine-tuned via layer-wise learning-rate decay (LLRD) along with data augmentation and Test-Time Augmentation (TTA). Testing was performed on a balanced dataset with 9,540 images: 8,000 for training, 770 for validation and 770 for testing. In the independent test dataset, the model achieved 91.65% accuracy, 91.55% F1-score, 91.56% sensitivity, 95.06% specificity, and 95.84% AUC-ROC. Test-time augmentation was applied to enhance the reliability of predictions without re-